【单选题】
A pair of spectacles ___ what I need at the moment.
A. is
B. are
C. has
D. have
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相关试题
【单选题】
— Five days ___ too long for me to wait.
A. was
B. were
C. is
D. are
【单选题】
You had better ___ a doctor as soon as possible.
A. seeing
B. saw
C. see
D. seen
【单选题】
The boy is not happy at the new school. He has ___ friends there.
A. few
B. a few
C. little
D. a little
【单选题】
I fell and hurt myself while I ___ basketball yesterday.
A. was playing
B. am playing
C. play
D. played
【单选题】
Tom ___ more than twenty pounds on the novel.
A. spent
B. paid
C. cost
D. took
【单选题】
Don't forget ____ the window before leaving the room.
A. to have closed
B. to close
C. having closed
D. closing
【单选题】
Twenty people were___ wounded in the air crash.
A. quickly
B. wrongly
C. bitterly
D. seriously
【单选题】
The top of the Great Wall is ___ for five horses to go side by side.
A. wide
B. so wide
C. wide enough
D. enough wide
【单选题】
We’ve missed the last bus. I'm afraid we have no ___but to take a taxi.
A. way
B. choice
C. possibility
D. selection
【单选题】
Nancy is considered to be ____ the other students in her class.
A. less intelligent
B. the most intelligent
C. intelligent as well
D. as intelligent as
【单选题】
It's _____ that he was wrong.
A. clearly
B. clarity
C. clear
D. clearing
【单选题】
There ____ a book and some magazines on the desk.
A. is
B. be
C. have
D. has
【单选题】
She is not only my classmate _____ also my good friend.
A. or
B. but
C. and
D. too
【单选题】
He asked the waiter ___ the bill.
A. on
B. of
C. for
D. after
【单选题】
_____ you are leaving tomorrow, we can have dinner together tonight.
A. Since
B. While
C. For
D. Before
【单选题】
I would like to do the job ___ you don't force me to study.
A. in case
B. although
C. though
D. as long as
【单选题】
The reason I did not go abroad was ___ a job in my home town.
A. because
B. due to
C. that I got
D. because of getting
【单选题】
_____ she survived the accident is miracle.
A. What
B. That
C. As
D. Which
【单选题】
I often see ____ the road on his way home.
A. he cross
B. him cross
C. him crossed
D. he crossing
【单选题】
His mother _______ alone since his father died.
A. lived
B. lives
C. has lived
D. is living
【单选题】
The workers are busy _____ models for the exhibition.
A. to make
B. with making
C. being making
D. making
【单选题】
It was well known that Thomas Edison _______ the electric lamp.
A. discovered
B. invented
C. found
D. developed
【单选题】
She wonders ____ will happen to her private life in the future.
A. that
B. it
C. this
D. what
【单选题】
The higher the temperature, _____ the liquid evaporates.
A. the faster
B. the more fast
C. the slower
D. the more slower
【单选题】
Australia is one of the few countries ______ people drive on the left of the road.
A. which
B. that
C. where
D. on which
【单选题】
Sunday is the day ____ people usually don't go to work.
A. when
B. which
C. in which
D. that
【单选题】
____ you know, David has been well lately.
A. Which
B. As
C. What
D. When
【单选题】
The harder you study, _____ you will learn.
A. much
B. many
C. the more
D. much more
【单选题】
They got there an hour _____ than the others.
A. early
B. much early
C. more early
D. earlier
【单选题】
The grey building is the place where the workers live, and the white building is the place where the spare parts ____ .
A. are producing
B. are produced
C. produced
D. being produced
【单选题】
Once environmental damage ______, it takes many years for the system to recover.
A. is to do
B. does
C. had done
D. is done
【单选题】
We worked hard and completed the task ___.
A. in the time
B. on the time
C. ahead of time
D. before time
【单选题】
I didn't expect you to turn _____ at the meeting yesterday.
A. up
B. to
C. out
D. over
【单选题】
I like the teacher _______ classes are very interesting and creative.
A. which
B. who
C. whose
D. what
【单选题】
When Lily came home at 5 p. m. yesterday, her mother ______ dinner in the kitchen.
A. cooked
B. was cooking
C. cooks
D. has cooked
【单选题】
I don’t know the park, but it's _____ to be quite beautiful.
A. said
B. told
C. spoken
D. talked
【单选题】
Mike is better than Peter ____. swimming.
【单选题】
The young lady coming over to us ______ our English teacher; the way she walks tells us that!
A. must be
B. can be
C. would be
D. could be
【单选题】
Eggs, though rich in nourishments, have ______ of fat.
A. a large number
B. the large number
C. a large amount
D. the large amount
【单选题】
Neither John ______his father was able to wake up early enough to catch the morning train.
A. nor
B. or
C. but
D. and
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发电机正常运行频率应保持在___Hz，允许变化范围为___Hz，可以按额定容量连续运行。频率变化时，定子电流、励磁电流及各部分温度不得超过___。
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我公司发电机定子额定电压___，定子额定电流___。
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我公司额定励磁电压___，额定励磁电流___。
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发电机定子电压允许在额定值范围___内变动，当功率因数为额定值时，其额定容量不变，即定子电压在该范围内变动时，定子电流可按比例相反变动。但当发电机电压低于额定值的___时，定子电流长期允许的数值不得超过额定值___。
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发电机运行的氢气纯度不得低于___，含氧量小于___。
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发电机转子额定电压___，转子额定电流___。
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发电机并列后有功负荷增加速度决定于___，无功负荷增加速度___，但是应监视定子电压变化。
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发电机转子绕组绝缘电阻用___摇表测量，绝缘值不得小于___。
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定子三相电流不平衡时，就一定会产生___电流。
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发电机在升压过程中检查定子三相电压应___上升，转子电流不应超过___。
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发电机转子空载电压___，转子空载电流___。
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发电机正常运行时，定子电流三相不平衡值一般不能超过定子额定值的___。
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